1. Field of the Present Invention
The present invention relates to a method of depositing a silicon-containing film.
2. Description of the Related Art
Conventionally, a vertical-type thermal processing apparatus is known that horizontally holds a plurality of wafers on a wafer boat so as to stack the wafers at intervals in a vertical direction like shelves, and accommodates the wafer boat holding the wafers in a vertically long process chamber. Then, a film is deposited on the wafers by supplying a predetermined gas into the process chamber and heating the process chamber.
Japanese Laid-Open Patent Application Publication No. 2011-254063 discloses a film deposition method using such a vertical-type thermal processing apparatus. In the film deposition method, a silicon film containing impurities in an amorphous state is deposited by alternately repeating a first gas supply process of supplying a silane-based gas composed of silicon and hydrogen into a process chamber so as to cause the silane-based gas to adsorb on a surface of an object to be processed and a second gas supply process of supplying a gas containing impurities such as BCl3 and the like into the process chamber.
Similarly, Japanese Laid-Open Patent Application Publication No. 2010-251654 discloses a film deposition method using the vertical-type thermal processing apparatus. In this method, a silicon nitride film containing boron is deposited by repeating a first process of forming a silicon nitride layer containing boron by supplying a silane-based gas (DCS, Dichlorosilane), a nitriding gas (NH3), and a boron-containing gas (BCl3) to a substrate in this order while purging the substrate with N2, and a second process of supplying a nitriding gas activated by plasma (activated NH3) to the silicon nitride layer containing boron in this order.
In the above-mentioned vertical-type thermal processing apparatus, because the inside of the process chamber is not divided, when different types of gases are supplied into the process chamber, the different gases mix and react with each other in the process chamber. To prevent such a reaction, in the film deposition method disclosed in Japanese Laid-Open Patent Application Publication No. 2011-254063, the supply of the silane-based gas is stopped while performing the purge process to expel the remaining silane-based gas after performing the first gas supply process, and then the supply of the gas containing the impurities is stopped while performing the purge process to expel the remaining gas containing the impurities after finishing the second gas supply process in order to alternately perform the first gas supply process and the second gas supply process. These series of processes are made in one cycle, and the film deposition is performed by repeating the above-mentioned cycle up to a predetermined number of times.
Similarly, even in the film deposition method disclosed in Japanese Laid-Open Patent Application Publication No. 2010-251654, as discussed above, a process of purging the substrate with N2 is performed between each of the processes of supplying the silane-based gas, the nitriding gas and the boron-containing gas, and one cycle is formed by adding a process of supplying the activated nitriding gas to the above-mentioned processes. The film is deposited by repeating this cycle.
In such a film deposition method, a first reaction gas is supplied to a substrate so as to cause the first reaction gas to adsorb on a surface of the substrate, and then a second reaction gas is supplied to the substrate so as to cause the second reaction gas to react with the first process gas adsorbed on the surface of the substrate, thereby depositing a film composed of a reaction product of the first and second reaction gases. This film deposition method is referred to as Atomic Layer Deposition (ALD) or Molecular layer Deposition (MLD).
However, in the above-mentioned configurations disclosed in Japanese Laid-Open Patent Application Publication No. 2011-254063 and Japanese Laid-Open Patent Application Publication No. 2010-251654, because the supply and the stop of the gas are frequently repeated, a substantial period of time is required to perform even one cycle. Moreover, this cycle needs to be repeated a plurality of number of times to deposit a film having a predetermined film thickness, which requires a very long period of time and substantially decreases productivity.
On the other hand, as disclosed in Japanese Laid-Open Patent Application Publication No. 2010-263245, a turntable-type film deposition apparatus is known as a film deposition apparatus to perform the above-mentioned ALD or MLD. Such a turntable-type film deposition apparatus includes a turntable on which a substrate is placed, a first reaction gas supply part to supply a first reaction gas to the turntable, a second reaction gas supply part to supply a second reaction gas to the turntable, and a separation area provided at a location between the first reaction gas supply part and the second reaction gas supply part to separate the first reaction gas from the second reaction gas. The separation area has a ceiling surface lower than ceiling surfaces of an area where the first reaction gas is supplied and an area where the second is supplied, and includes a separation gas supply part to supply a separation gas.
The turntable-type film deposition apparatus using ALD or MLD can perform the film deposition method disclosed in Japanese Laid-Open Patent Application Publication No. 2011-254063 and Japanese Laid-Open Patent Application Publication No. 2010-251654 with high productivity. More specifically, the turntable-type film deposition apparatus can perform the above-mentioned one cycle by one revolution of the turntable, and the plurality of cycles can be continued by rotating the turntable multiple number of times of revolutions without stopping the supply of the gases.
However, because the turntable-type film deposition apparatus differs from the above-discussed vertical-type thermal processing apparatus in apparatus configuration and temperature conditions in the film deposition process, a high-quality film cannot be necessarily obtained even if the turntable-type film deposition apparatus performs the film deposition method disclosed in Japanese Laid-Open Patent Application Publication No. 2011-254063 and Japanese Laid-Open Patent Application Publication No. 2010-251654.